Janáček was born in Hukvaldy in Moravia, the son of a schoolmaster. As a boy, he sang in the choir of the monastery in Brno. He later went to Prague to study music, and made a living as a music teacher. He also conducted various amateur choirs. In 1881, he moved back to Brno, and founded the Organ School there, which was later to become the Brno Conservatory.

As a young man, Janáček became friends with Dvořák, and began composing in a relatively traditional romantic style, but after his opera Sárka (1881), his style began to change. He made a study of Moravianfolk music and used elements of it in his own music. He especially focused on studying and reproducing the rhythm and the pitch contour and inflections of normal Czech speech, which helped in creating the very distinctive vocal melodies in his opera Jenůfa (1904). Going much farther than Modest Mussorgsky and anticipating the later work of Béla Bartók in such styles, this became a distinguishing feature of his vocal writing (Samson 1977). When Jenůfa was given in Prague in 1916, it was a great success, and brought Janáček real acclaim for the first time. He was 62 at the time, and began to compose the pieces he is now best known for, what many consider his, belatedly, mature style. A year later, he met Kamila Stösslová, a young woman who who was a profound inspiration to him for the remaining years of his life.

His work is tonal, though a vastly expanded tonality, and marked by unorthodox spacings, often making use of modality: 'there is no music without key. Atonality abolishes definite key, and thus tonal modulation....Folksong knows of no atonality.' (Hollander 1963) He uses accompaniment figures and patterns prominently, with, according to Jim Samson, 'the on-going movement of his music...similarly achieved by unorthodox means—often a discourse of short, 'unfinished' phrases comprising constant repetitions of short motives which gather momentum in a cumulative manner.' (Samson 1977)